A shipping traffic officer in Tanjung Priok, North Jakarta, Suyadi, told The Jakarta Post that he has received a report from a tugboat, AS Jaya II, that the crew had seen a downed plane in Tanjung Bungin in Karawang, West Java.

Camera IconThe flight path followed by the Lion Air flight.

"At 7:15am the tugboat reported it had approached the site and the crew saw the debris of a plane," Suyadi said.

As of 9am there was no report about passengers or the plane crew, he said.

Two other ships, a tanker and a cargo ship, near the location were approaching the site, he said, and a Basarnas rescue boat was also on the way.

Indonesia’s state air navigation operator AirNav has alerted search and rescue authorities, spokesman Yohannes Harry Douglas said in a text message. Air spokesman Danang Mandala Prihantoro said "we can confirm that one of our flights has lost contact, its position cannot be ascertained yet".

The Flightradar website tracked the plane, showing it looping south on take-off and then heading north before the flight path ended abruptly over the Java Sea, not far from the coast.

Camera IconBelongings reportedly found during the search for the Lion Air plane. Credit: @Sutopo_PN/Twitter

The plane involved was a Boeing Co 737 Max-8 model. The aircraft is believed to be just two months old, and a significantly updated version over older 737 models.

The last major accident in Indonesia was in December 2014 when AirAsia Indonesia’s Airbus A320 aircraft crashed into the waters after taking off from Surabaya to Singapore with 162 people on board.

Indonesia relies heavily on air transport to connect its thousands of islands but has a poor aviation safety record and has suffered several fatal crashes in recent years.

A 12-year-old boy was the sole survivor of a plane crash that killed eight people in mountainous eastern Indonesia in August.

In August 2015, a commercial passenger aircraft operated by Indonesian carrier Trigana crashed in Papua due to bad weather, killing all 54 people on board.